In the case of motor vehicle seats, there is a growing tendency to equip the seat base with height adjustability with respect to the seat travel device for longitudinal adjustments consisting of two pairs of runners. In the case of a seat underframe of the above-mentioned kind, the height adjustment device has rear rockers, namely a left-hand and a right-hand rear rocker. They support the seat base in its posterior area. The seat base must also be supported in its front area. It is also possible to provide rockers, namely front rockers, which are nevertheless devices of different construction, such as, for example, curved guide rails for axle pins on the front edge of the seat, etc.
A high level of safety is required of seat underframes, in particular, the safety belt must be anchored to them in such a fashion that the entire vehicle seat is capable of withstanding the loads which it is subjected to during the prescribed test trials. The construction of the seat underframe must also be of such a type as to be of as low a total weight as possible, capable of being set up and mounted simply, in addition to being easily recyclable. The mounting points for the safety belt, especially for the lap belt, must be embodied and arranged in such a way that their configuration is serviceable on the one hand and that the components into which the forces released by an accident are to be induced, on the other hand, are able to absorb these forces well without having to be of heavy construction with dimensions which are too large, resulting in a weight that is too high.
This is where the invention starts. It is the task of the invention to further develop the seat underframe of the above-mentioned kind in such a way, that the safety belt, especially the lap belt of this safety belt, is positioned in such a fashion as to be not only convenient to the user but also capable of absorbing high forces arising in the course of an accident, the individual components being of reasonable dimensions.